This project involves nonhuman primates of the species Erythrocebus patas, Macaca fascicularis, and, in collaboration with Oak Ridge Associated Universities, Saguinus oedipus. The finding that chronic ulcerative colitis in the cotton-top tamarin, Saguinus oedipus, is associated with a high incidence of multifocal colonic carcinoma presents a unique opportunity to study the etiology of colonic carcinoma in a system that strikingly mimics the comparable association of ulcerative colitis and colonic carcinoma in humans. In collaboration with Dr. Neal Clapp of Oak Ridge Associated Universities, we have undertaken several studies to explore the etiology of tamarin chronic carcinoma. Current studies are directed toward possible participation to tumor suppressor genes in this disease. A survey of patas monkeys for immunodeficiency virus related antigens including SIV, SRV-1, SRV-2, SRV-5, and STLV-L was uniformly negative, which is intriguing in view of the successful isolation by others of SIV related to HIV-2 from other African species more or less closely related to patas (cf. project Z01CP05301). Biochemical studies on pleiotropic enzyme induction following exposure to phenobarbital and its relationship to tumor promotion continued (cf. project Z01CP05299), together with investigation of metabolism and pharmacokinetics of carcinogenic N-nitrosamines and the effects of ingested ethanol on these parameters.